A former corrections officer who was at the center of a months-long investigation into the 2008 asphyxiation of an accused cop killer at the Prince George's County jail pleaded guilty Friday to obstructing justice, admitting that he gave police a false account of an incident that has remained murky for more than four years.

Anthony McIntosh, 49, who was allowed to resign from the county's Department of Corrections a year after the prisoner's death, is so far the only person to be charged with a crime in the death of 19-year-old Ronnie L. White, who either hanged himself or was strangled by an attacker in a maximum-security cell.

McIntosh has admitted covering up key aspects of the incident. But he has not been accused of killing White and has denied any involvement in his death.

White, who was found unconscious beside his bunk June 29, 2008, had been locked up two days earlier for allegedly killing Prince George's Cpl. Richard S. Findley by running him down with a stolen truck. White's jailhouse death ignited angry public controversy over whether he had been a victim of vigilante justice or had committed suicide.

A medical examiner ruled White's death a homicide, but an extensive Maryland State Police probe concluded that it was possible he had taken his own life.

Appearing in U.S. District Court in Greenbelt, McIntosh, clad in a dark suit and tie, pleaded guilty to one count of lying to investigators about the circumstances of White's death. Federal guidelines call for a prison term of 24 to 30 months. Judge Alexander Williams Jr. scheduled sentencing for April 8. McIntosh remains free on his own recognizance.

Forrest Christian, a Justice Department lawyer handling the case, declined to comment afterward. Members of White's family were in the courtroom but did not speak with reporters later.

Several days into the 2008 investigation, McIntosh told officials that he found White hanging from his bunk with a bedsheet noose around his neck about 10:15 a.m. Worried that he would be disciplined over a suicide, McIntosh said, he did not report the incident. He said he removed the sheet from White's neck in a panic and left him on the floor.

Another guard said he summoned help after finding White unconscious next to his bunk while delivering his breakfast about 10:30 a.m. The absence of the bedsheet noose, which initially caused a possible suicide to look more like a homicide, has perhaps permanently muddied the true circumstances of White's death.

"More significant" than White's plea is "what the plea does not say," defense lawyer Deborah Boardman said after the hearing.

"Ronnie White's death was tragic. But Anthony McIntosh did not harm, kill or cause the death of Ronnie White." She said that the past 4 1/2 years have been "very painful" for her client and that he looks forward to a fresh start after prison.

In return for the plea, the Justice Department agreed not to prosecute charges of obstructing justice and violating White's civil rights by failing to call for medical aid.

With Friday's plea, an inquiry that lingered unresolved for 56 months appears to be closed. In a separate civil case, court records indicate that White's family received a $500,000 settlement in a lawsuit against the county.

A medical examiner's report in 2008 said White had been strangled, probably with a sheet, a towel or the "crux of an elbow."

But after a year of investigation, the Prince George's state's attorney announced in June 2009 that authorities had not found enough evidence to warrant charging anyone with killing the prisoner.

Federal authorities then took up the case, obtaining a three-count indictment of McIntosh.

The incident occurred in a maximum-security unit where three guards were on duty, authorities said. One of them, Russell Hardesty, never left the unit's enclosed control booth, his attorney said. The others were McIntosh and Ramon Davis, who reported finding White. Unlike McIntosh, Davis did not have access to the cell, officials said.

Investigators said they closely examined a rolled-up bedsheet found in the cell. They said a pattern of wrinkles suggested that it had been tightly wound from one corner. The sheet could have been used as a strangulation instrument, as the medical examiner indicated, or it could have been used as a suicide noose, investigators concluded.

There were six holes, each an inch in diameter, in the cell's top bunk. Investigators said they tested whether a sheet could be threaded through one of the holes and tied to make a noose. They determined that it was possible.

And after an extensive investigation of McIntosh's background, authorities said, they decided that he was an unlikely killer, both physically and by disposition. Supervisors labeled him "soft" and a "dough boy." At 5-foot-9 and 220 pounds, investigators said, McIntosh probably could not have overpowered the younger, more athletic prisoner.